Roofing material with locally applied fire resistant material

Abstract

A roofing shingle having fire resistance material added to the shingle in a localized area includes a substrate having a first portion and a second portion, a first asphalt-based coating impregnating the first portion, the first asphalt coating including a fire retardant material, and a second asphalt-based coating impregnating the second portion, the second asphalt coating containing less of the fire retardant material than the first asphalt coating.

The invention claimed is: 
     
       1. A roofing shingle, comprising:
 a substrate having a first portion and a second portion; 
 a first asphalt coating containing asphalt and a fire retardant material, the first asphalt coating and fire retardant material impregnating the first portion and forming a layer on a bottom side of the first portion; 
 a second asphalt coating impregnating the second portion, the second asphalt coating containing less of the fire retardant material than the first asphalt coating; and 
 a layer of granules applied onto at least a portion of a top side of the substrate. 
 
     
     
       2. The roofing shingle of  claim 1  wherein the second asphalt coating contains none of the first retardant material. 
     
     
       3. The roofing shingle of  claim 1  wherein the fire retardant material is intumescent. 
     
     
       4. The roofing shingle of  claim 1  wherein the fire retardant material is expandable graphite. 
     
     
       5. The roofing shingle of  claim 1  wherein the first asphalt coating includes about 0.25% to about 6.0% by weight of one or more materials from the group consisting of expandable graphite, ammonium polyphosphates and Borax or about 4% to about 20% by weight of one or more materials from the group consisting of colemanite, aluminum trihydrate, and magnesium hydroxide. 
     
     
       6. The roofing shingle of  claim 1  wherein the substrate comprises an overlay sheet laminated to an underlay sheet along a common bond area, and wherein the first portion is in, or proximate to, the common bond area. 
     
     
       7. The roofing shingle of  claim 6  wherein the first portion is located such that when the shingle is exposed to high heat, the fire retardant material obstructs the flow of liquefied asphalt from the common bond. 
     
     
       8. The roofing shingle of  claim 1  wherein the substrate is a first substrate that is configured to overlay a second substrate, and wherein the first portion is proximate to the location where the first substrate overlays the second substrate. 
     
     
       9. A method for manufacturing a roofing shingle having a substrate, comprising:
 forming a first asphalt coating comprising a mixture of asphalt and a fire retardant material; 
 forming an asphalt coated sheet by applying the first asphalt coating to a first portion of the substrate and applying a second asphalt coating containing asphalt and less of the fire retardant material than the first asphalt coating to a second portion of the substrate; and 
 applying granules to a top side of the asphalt coated sheet to form a granule coated sheet, 
 wherein the asphalt and fire retardant material of the first asphalt coating impregnates the first portion of the substrate and the asphalt of the second asphalt coating impregnates the second portion of the substrate. 
 
     
     
       10. The method of  claim 9  wherein the second portion is impregnated with none of the fire retardant material. 
     
     
       11. The method of  claim 9  wherein the first portion is in, or proximate to, the common bond area. 
     
     
       12. The method of  claim 9  wherein the fire retardant material is intumescent. 
     
     
       13. The method of  claim 9  wherein the fire retardant material is expandable graphite. 
     
     
       14. The method of  claim 9  wherein the substrate is a first substrate that is configured to overlay a second substrate, and wherein the first portion is proximate to the location where the first substrate overlays the second substrate. 
     
     
       15. The method of  claim 9  wherein the first asphalt coating impregnates at least a bottom side of the substrate in the first portion. 
     
     
       16. The method of  claim 9  further comprising:
 separating the granule coated sheet into an underlay sheet and an overlay sheet; and 
 laminating the overlay sheet onto the underlay sheet along a common bond area. 
 
     
     
       17. The method of  claim 16  wherein the first portion is in, or proximate to, the common bond area. 
     
     
       18. The method of  claim 16  wherein the first portion is located such that when the shingle is exposed to high heat, the fire retardant material obstructs the flow of liquefied asphalt from the common bond area.